Concentrator



w. TYLER. CONCENTRATOR. APPLICATION FILED DEC ZQ, 1917.

Patented Nov. 22 MEL mm m o 2 SHEETSSHET I,

A. w. TYLER. CONCENTRATOR. APPLICATION FILED DEC-29, [9]].

' Patented Nov. 22

option. 1

ALvA w. TYLER, or LOS ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGNMENTS 'ro WALTER YOUNG, or LOS ANenLns, oAmroaiviA- CONCENTRATOR.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed December 29, 1917. Serial No. 209,404.

fication of the material being concentrated and travel of the material in a certain defi table surface, and on the return stroke the frictional resistance is overcome by the inertia of the forward moving material during the quick return of the table surface. The quick return demands relatively high consumption of power and is the cause of rapid destruction of the concentrator.

An object of this invention is to avoid frictional resistance of the material on the table on the return stroke thereof so as to reduce power consumption to a minimum.

Another object is to effect the same rate of travel of the table in both directions and to begin the strokes with a gradual acceleration and to end the strokes with a gradual retardation so as to prolong the useful like of the concentrator.

Another object is to make provision for moving the table in different paths of travel on its forward and back strokes so that at some part of the stroke the body of ore will be spaced from the table surface.

Another object is to provide a motion of the concentrator tablesuch'as will enable the ore to travel over the table when the table is. aslant upward toward the discharge end so as to maximize the concentrating effect of the table movement on the ore.

Other objects are simplicity of construction and the production of such movement of the concentrator table as is capable of effecting rapid stratification and concentralZIOII of the material, with a relatively 'high efiiciency due to simplicity of the motion mechanism and low cost of operation and up-keep.

The accompanying drawings illustrate the invention:

Figure is a side elevation of a'concentrator equipped with the invention.

Fig. 2 is an enlarged fragmental plan yiew, partly in section, of the table vibrating mechanism shown in Fig. 1.

-F1g. 3 is an elevation, partly in section, from line m m Fig. 2, the cover plate of the cam housing being omitted for clearness of illustration.

Fig. 4 is an elevation, partly in. section, from line w a9-, Fig. 2, the shaft shoulder and cover plate of the cam housing being omitted for clearness of illustration.

Fig. 5 is a view of the shaft at the left end of Fig. 2, detached, the sprocket wheel, cam and pulley being assembled on said shaft.

Fig. 6 is an enlarged detail of the cam adjustin device.

Figs.

Fig. 13 is an enlarged transverse sectionon the line indicated by m a: ,Fig. 11, the table being shown tilted toward its discharge side. Arrows indicate the paths of the air currents and the treated material.

Fig. 14 is a transverse section through two of the riffles of the table, the material being treated being shown and the direction of transverse flow of the material and the paths of the air currents being indicated by arrows.

to 1 inclusiveare diagrammatic views illustrating the paths of movement of A concentrator frame is shown at 1 and p the table therefor at 2. Air is supplied to the table by a blower 3 or other suitable air pumping device. The "detailed construction of the concentrator table need not be shown and described herein since any suitable construction may be employed. The concentrator table illustrated in Figs. 1 and 11 to 13 inclusive is analogous, to that disclosed by me in Letters Patent No. 1,262,603,

grantedApril 9th, 1918.

The concentrator table'2 is hinged near opposite ends at 4 to a horizontallydisposed vlbratory arm 5 which may be adjustably connected as at 6 to the table 2 for purposes of regulating the transverse inclination of the table. The adjustable connection 6 need not be described in detail herein since it may be of any well known construction. The frame is pivoted at 7 to a base 8 and tilting of the table lengthwise is effected by means of a vertical screw 9 engaging the frame, there being a bolt 10 to lock the frame in adjusted position on the base.

The arm 5 is connected with the frame 1 by vertical-motion eccentric devices andhorizontal-motion eccentric devices so that the arm, and with it the table, may be moved endwise and up and down. One end of the arm 5 may be provided with both vertical and horizontal-motion eccentric devices and the other end of the arm may be normally connected with the frame in any well known manner, but I have shown it connected by vertical-motion eccentric devices. The eccentric devices will now be described in detail. The arm 5 is furcatedat its opposite ends to form housings for the eccentrics and the furcations at one end of the arm are provided in their chambers 11 with eccentric straps 12 in which rotate eccentrics 13. Preferably antifriction bearings 14 will be interposed between the straps 12 and eccentrics 13. The eccentrics 13 may be constructed in any suitable manner and in the instance shown in the drawings said eccentrics comprise collars 14 mounted .on hubs 15 which may be integral with a shaft 16 extending transversely of the table 2 and rotatively mounted in a bearing 17 of the concentrator frame 1.

The furcations at the other end of the arm 5 are provided with chambers 18 in one of which are eccentric straps 19, 20 and in the other of which are eccentric straps 21, 22. Rotatively mounted in the eccentric straps 19, 20, 21, 22 are eccentrics 23, 24, 25, 26 respectively, and preferably antifriction bearings 27 are interposed between the'straps and eccentrics. The eccentrics 23 to 26 may be constructed the same as described above for the eccentrics 13. V

The eccentric 23is partly formed integral with a shaft 28 which extends transversely 85 of the table 2 and is provided with a eer/nee .35, in this case formed separate from the sleeve, bearing against the inner faces of the furcations of the arm 5-so as to pre-' vent relative movement between the sleeve 32 and said arm and to exclude dust from the bearings.

The eccentric 26 is partly formed integral with a sleeve 36 which is rotatively mounted in a bearing 37 of the concentrator frame 1. This sleeve 36 surrounds the reduced portion of the shaft 28 and said reduced portion projects beyond the outer end of the sleeve 36 and is screw-threaded at its end toreceive a nut TVhen the nut 38 is 90 tightened against thesleeve 36 it forces the Alf] sleeve 32 with its seat 33 tight against the shoulder 34. The reduced portion of the shaft 28 is provided with means such as a pin 39 engaging a slot 40 in the sleeve 36 to hold said sleeve and the shaft against relative turning, thus to hold the eccentrics 23 and 26 against relative turning. These eccentrics 23 and 26 are in corresponding positions circumferentially of the shaft and the eccentrics 24, 25 are also in correspond ing positions circumferentially of the shaft and in different positions than the eccentrics 23, 2e. 1

The positions of the eccentrics 24, 25 may be adjusted relative to those of the eccentrics 23, 26 and for this purpose the sleeve 32 (see Fig. 6) is provided with a collar 41 having an arm 42, there being means such as a set screw 43 to hold the collar against turning relative to the shaft. The standard 43 is provided with a disk 44 which may he graduated as indicated at 45 and by loosening" the nut 38 the arm 42 and disk 44 may 1115 be turned relative to one another so as to produce relative'adj'ustment between the eccentrics 24, 25 and the eccentrics 23, 26B When the desired adjustment has been made the nut 38.will be tightened so that the ad- 12 justment will be maintained. The gradua- .tions 45 may indicate degrees or parts of degrees of circular measurement so that the air of eccentrics 23, 26 can be readily ad usted with their .high points at any desired number of degrees and fractions of degrees from the high points of the pair of eccentrics 24, 25.

The shaft 28 rotates in a bearing 46 of the frame 1 and may be provided with a pulley 47, which is shown fragmentarily in Fig. 2, or other means whereby power may be readily applied to the shaft to operate the concentrator.

The eccentric straps 12, 19, 22 are seated in blocks 48 which are free to move horizontally between guides 49 in the form of wedges which rest on inclined faces .50 of the chambers 11, 18. The guides 49 may be adjusted endwise to take up wear by turning screws 51. The guides 49 thus prevent vertical motion of the blocks 48.

The eccentric straps 20, 21 are seated in blocks 52 which are free to move vertically between guides 53, 54, the guides 53 being formed by certain vertical faces of the chambers 18 and the guides 54 by a wedge-shaped member resting against inclined faces 55 of the chambers 18. The guides 54 may be adjusted endwise to take up wear by turning screws 56. The guides 54 thus prevent horizontal motion of the block 52.

From the foregoing it is clear that rotation of the eccentrics 13, 23, 26 causes horizontal motion of the blocks 48 relative to the arm 5 so as to be inefiectual to transmit horizontal motion to said arm and that said eccentrics operate to cause up and down motion of the arm and therefore of the table 2; and also that rotation of the eccentrics 24, 25 causes vertical motion of the blocks 52 relative to the arm 5 so as to be ineffectual to transmit vertical motion to said arm and that said eccentrics 24 25 operate to cause to and fro motion 'of the arm and therefore of the table.

The up and down motion caused by operation of the eccentrics 28, 26 corresponds in time with that caused by operation of the eccentrics 18.

The chambers 11, 18 may be provided, as shown, with cover plates 57 held in place by screws 58.

The foregoing described mechanism operates as foilows: When the pulley 47 is driven through the agency of a belt or the like by any suitable pmver the eccentrics will all be turned as is obvious. Now refer to 7 in which (5' is the low point on the eccentrics and It the high point. First assuming that the pair of eccentrics 23 28 is adjusted so that their high points are 45 of circular measurement from the high points of the pair of eccentrics 24, 25, that the table 2 is at the lowest point (Z, that the direction of rotation of the shaft 28 is coun fer-clockwise as indicated by the arrow in said figure and that the table slopes, for instance, upward to the right, the movement of every portion of the table surface will be in a slight curve forward and upward from (Z to e and thence from e to f. This movement corresponds to 90 of revolution of the shafts 16, 28 and one-half of the upward stroke occurs while a relatively larger portion of the horizontal stroke is made or, in other words, during the period of time of this movement the horizontal movement has a predominating effect on the material. The result of this movement is to give the material lying on the table a relatively quick forward and relatively slow upward im-- pulse, the horizontal component of said impulse being the greater.

As the shafts 16, 28 revolve the eccentrics through another 45 the table is moved forward and upward from f to g, the vertical component relative to the horizontal component being much greater than the vertical component relative to the horizontal component during the movement from (I to f.

Turning of the shafts 16, 28 through another 45 causes the table to move backward and upward from g to 72,. The movement from f to it gives the material on the table a sudden upward impulse for a short period of time just prior to, during and subsequent to reversal of the horizontal stroke.

As the shafts 16, 28 rotate the eccentrics through another 90 of circular measurement the table moves backward and downward in the path h-ic, but the material which has been given a forward and upward impulse, as noted above, continues its forward and upward movement for an instant due to the inertia of said materiai and during this movement of the material the table moves away therefromdownward in the path h-Jc and consequently no frictional resistance exists between and the material at the time of this reverse stroke.

Turning of the shafts through another 45 causes the table to move haclrward and downward in the path is -m the movement being relatively slo and downward movement being relat The speed of the machinewiil he ed that the action of gi'a y w material again in contact w face at substantially the in.. on its next forware st: nap -#2. During the latter p tion and then drops more reversal point an to its lovi When the tahle reaches material has fallen upon it then starts slowly forward ag n repeat the cycle of movements as above described. As the table moves forward and downward slowly from m to Z the ma'iterial will again be put into moti n by the table without undue friction of the material due to the inertia thereof since its rearward motion has been stopped at least in part by the force of gravity acting on the ore particles from the time they are thrown from the table to the time of their alighting on the table.

The angular velocity of the shafts may be made such that the table surface will move from its highest position backward to its point of horizontal reversal while the force of gravity, plus the upward fluid pressure of the air from the blower 3 through the perforated surface of the table, is overcoming the inertia of the material, the force of gravity acting through the vertical dis tance between the horizontal planes passing through h, m, respectively.

The upward fluid pressure on the material will vary during the cycle of movements of each particle of the material due to the fact that the bed of material covering the table surface and acting as a sort of blanket or a buffer is relatively traveling away from the table surface at one instant and toward it at another, thus relieving and increasing the pressure alternatively. Thus a puffing effect is produced which is favorable to the rapid separation and stratification of the different classes of material according to the specific gravities of the particles constituting said material. This puffing effect has been heretofore attempted in other ways by various more complicated and less efficient constructions.

In Fig. 7 the high points d of the eccentrics 23, 26' are 45 in advance of the high points d of the eccentrics 24, 25. Thus it is clear that the table is moved in an elliptical path, the major axis of the ellipse being oblique to the horizontal, and the lowermost position of the table occurs subsequent to the beginning of the forward stroke and the highest position of the table occurs subsequent to the beginning of the back stroke.

The effect of the above described movements has been thoroughly tested on practically all kinds of ores and has proven very successful in the operation of pbtaining concentrates.

In Figs. 7 to 10 different points in the path of movement of any given point on the table surface are. indicated. by, letters and corresponding points on the eccentrics 24, 25 are indicated by the same letters primed and corresponding points on the eccentrics 23, 26 are indicated by the same letters with the exponent 2.

Fig. 8 illustrates the path of movement of the table produced by relatively adjusting the eccentrics so that the high points of the eccentrics 23, 26 are 90 in advance of the high pointsof the eccentrics 24, 25'. by this adjustment, assuming that the eccentrics are being rotated in the direction of the arrow, every portion of the table will move in an oblique path from its lowest po-' sition d to its highest position it and then rearward in the same path.

In Fig. 9 the eccentrics are adjusted so that the high points of the eccentrics 23,

26 coincide'with the high points of the ecceneccentrics 23, 26 are 45 behind or 315 in advance of the high points. of the eccentrics 24, 25. In this instance the major axis of the elliptical path is oblique to the horizontal and the lowermost position ofthe table occurs just before the end of the forward stroke of the table and the highest position occurs just prior to the end of the backward stroke of the table.

In the drawings the eccentrics 24, 25 are shown larger than the eccentrics 23, 26 and it is understood that the relative-sizes of the eccentrics may be as desired for obtaining any degree of horizontal and vertical throw. 1

The invention is not limited to the' adjustments of the eccentrics capable of producing the movements depicted in Figs. 7 to 10 for it is obvious that in practice it may be desirable to modify the movement of the table by other adjustments of the eccentrics; and it may be desirable at times to adjust the table so that it slopes downward toward its discharge end.

From the foregoing it will be readily understood, that by setting the eccentrics so that the high points of the eccentrics 23, 26 are135 behind the high points of the eccentrics 24, 25 and rotating said eccentrics opposite to that indicated by the arrow in Fig.

thesame path of movement and direction of said movement of the table will be traced as that shown in said figure.

.If, as hereinbefore suggested, the arm be movably connected with the frame 1 by the well known link instead of the eccentric device, it is clear that the end of the table adjacent the eccentrics will be given the full motion of the eccentrics as above described, and that the intensity of such motion will gradually diminish toward the discharge end of the table to zero at a point immediately above the link. In practice this operation is also very' effective in concentrating the ore.

It is clear from-the foregoing that the table 2 and the arm 5 are moved in an endless path extending ina vertical plane, and that the movement is faster at some portions of said path than at other portions thereof.

A newmethod is effected by the operation of the above described concentrator and such method consists in causing the ore to move away from a reciprocating supporting surface for an interval of time while the surface is moving in one direction so as to eliminate friction\between the ore and the surface causing movement thereof. The method also consists in delivering a current air beweave-e neath the ore supporting surface while the ore moves up and down so as to cause.decreased air pressure beneath the ore when the ore moves up and to cause increased air pressure beneath the ore when the ore falls toward the supporting surface. The method also consists in imparting alternative forward and backward motions to the ore, and overcoming in part the backward motion of the particles by the aid of gravity while the particles are free from the impelling surface. The method furthermore consists also in directing a current of air upward beneath the particles to further aid in overcoming the backward motion of the particles.

I claim:

1. In a dry ore concentrator, a table having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to move a portion of the table in an elliptical path.

2. In a dry ore concentrator, a table having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to move the table in an elliptical path.

3. In a dry ore concentrator, a table having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to move a port on of the table in an elliptical path, the major axis of the ellipse being oblique to the horizontal.

4. In a dry ore concentrator, a table having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to move a port on of the table in an elliptical path, the ma or axis of the ellipsebeing aslant upward toward the discharge end of the table.

5. In a dry ore concentrator, a table having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to impart relatlvely slow forward motion to the table and relatively quick upward motion near the end of the forward motion so as to throw material upward from the surface of the table.

6. In a dry ore concentrator, an arm, a table mounted on said arm and having a perforated ore-supporting surface, means to blow air upwardly through the perforations, a frame, vertical and horizontal-motion devices connecting the frame to the arm, and means to operate said devices.

7. In a dry ore concentrator, an arm, a table mounted to tilt transversely on said arm and having a perforated ore-supporting surface, means to blow air upwardly through the perforations, a frame, motion mechanism connecting the arm to the frame, and means to tilt the frame lengthwise.

8. In a dry ore concentrator, an arm, a table mounted on said arm and having a perforated ore-supporting surface, means'to blow air upwardly through the perforations, a frame, a vertical-motion eccentric device and a horizontal-motion eccentric device connecting one end of the arm to the frame, means movably connecting the other end of the arm to the frame, and means to drive the eccentric devices.

9. In a dry ore concentrator, an arm, a table mounted on said arm and having a perforated ore-supporting surface, means to blow air upwardly through the perforations, a ,vertical-motion eccentric device connected to each end of the arm, a horizontal-motion device connected toone end of the arm, and means to drive the eccentric devices.

10. In a dry ore concentrator, an arm, a table mounted on said arm and having a perforated ore-supporting surface, means to blow air upwardly through the perforations, a frame, a vertical-motion eccentric device connecting one end of the arm to the frame, vertical and horizontal-motion devices connecting the other end of the arm to the frame, and means to drive the eccentric devices.

11. In a dry ore concentrator, an arm, a table mounted on said arm and having a perforated ore-supporting surface, means to blow air upwardly through the perforations, vertical and horizontal-motion eccentric devices for operating one end of the arm, means movably supporting the other end of the arm, and means for adjusting the vertical-motion eccentric device relative to the horizontal-motion device to produce different motions of the arm.

' 12. In a dry 0re concentrator, a table, an arm supporting the table, a frame, -means movably connecting one end of the arm to the frame, a shaft journaled in the frame, an eccentric fast on the shaft, sleeves on the shaft, means to prevent relative rotation-of the sleeves and shaft, an eccentric fast on one sleeve, a pair of eccentrics fast on the other sleeve, blocks mounted in the arm shift'able only endwise thereof, other blocks mounted in the arm shiftable only vertically thereof, eccentric straps supported in the first named blocks for the first and second named eccentrics respectively, and eccentric straps supported in the second named blocks for the last named eccentrics respectively, the first and second named eccentrics having their high points at different circumferential positions than the high points of the last named eccentrics.

13. In a dry ore concentrator, a table, an arm supporting the table, a frame, means movably connecting one end of the arm to the frame, a shaft journaled in the frame, two eccentrics mounted on the shaft to turn therewith, said eccentrics having their high points at different circumferential positions from one another, blocks mounted in the other end of the arm, one of said blocks being shiftable only endwise of the arm and the other block being shiftable only vertically of the arm, andeccentric straps supported in the blocks for the eccentrics respectively.

14. In a dry ore concentrator, a table, an arm supporting the table, a frame, means movably connecting one end of the arm tothe frame, a shaft journaled in the frame, two eccentrics mounted on the shaft, means to adjust one of the eccentrics relative to the other to change the circumferential relations to one another of the high points of the eccentrics, blocks rmounted in the other end to prevent relative rotation of the shaft and one of the sleeves,'means to adju stably fix the other sleeve relative to the shaft, blocks mounted in the other end of the arm, a pair of said blocks being shiftable only endwise of the arm and a pair of said blocks being shiftable only vertically of the arm, and eccentric straps supported in the blocks respectively for the respective eccentrics.

16. In a dry ore concentrator, a tab1e,'an arm supporting the table, a frame, shafts journaled in the frame, an eccentric on one of said shafts, a block mounted in one end of the arm and shiftable only endwise thereof, an eccentric strap mounted in the block for said eccentric, eccentrics mounted on the other shaft to turn therewith, blocks mounted in the other end of the arm, one-of said last named blocks being shiftable only endwise of the arm and the other of the last named blocks beingshiftable only vertically of the arm, eccentric straps supported in the last named blocks respectivelyfor the respectlve last named eccentrics, and means operatively connecting the shafts to one another.

v17. In a dry ore concentrator, a table, an arm supporting the table, a frame, shafts journaled in the frame, an eccentric on one of said shafts, a block mounted on one end of the arm and shiftable only endwise there.

trics fast on the other sleeve, means to prevent relative rotation of the shaft and one of the sleeves, means to adjustably fix the other sleeve relative to the shaft, blocks mfiinted in theother end of the arm, a pair of said last named blocks being shiftable only endwise of the arm and a pair of said last named blocks being shiftable only vertically of thearm, eccentric straps supported in the last named blocks respectively for the eccentrics on the other shaft and on .the sleeves respectively, and means operatively connecting the shafts to one another.

18. In a dry ore concentrator, a table having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to move'the table iIi an endless path extending ina vertical ane. a 1 p 19. In a dry ore concentrator, a table having a perforated ore-supporting surface,

means to blow air upwardly through the perforations, and means to move the table in an endless path extending in avertical plane, the movement being faster at some portions of said thereof.

20. In combination, an arm, a frame,

means movably connecting one end of the arm to the frame, a shaft journaled in the frame, an eccentric. fast on the shaft, sleeves on the shaft, means to'prevent relative rota tion of the sleeves and shaft, an eccentric fast on one sleeve, a pair of eccentrics fast on the other sleeve, blocks mounted in the arm shiftable only endwise "thereof, other blocks mounted in the arm shiftable only.

frame, two eccentrics mounted on the shaft to turn therewith, said eccentrics having their high points at different circumferential positions from one another, blocks path than at other portions mounted in the other end of the arm, one of said blocks being shiftable only endwise of the arm and the other block being shiftable only vertically of the arm, and eccentric straps supported in the blocks for the eccentrics respectively.

22. In combination, an arm, a frame, means movably connecting one end of the arm to the frame, a-shaft journaled in the frame, two eccentrics mounted on the shaft,

means to adjust one of the eccentrics relative tothe other to change the circumferential relations to one another of the high points of the eccentrics, blocks mounted in the other end of the arm, one of said blocks means movably connecting one end of the arm to the frame, a shaft journaled in the frame, an eccentric fast on the shaft, sleeves on the shaft, an ecoentricfast on one sleeve, a pair of eccentrics fast on the other sleeve, means to prevent relative rotation of the shaft and one of the sleeves, means to adjustably fix the other sleeve relative to the shaft, blocks mounted in the other end of the arm, a pair of said blocks being shiftable only endwise of the arm and a'pair of said blocks beingshiftable only vertically of the armr, and eccentric straps supported in the blocks-respectively for the respective eccentrics.

24. In combination, an arm, a frame, shafts journaled in the frame,.an eccentric on one of said shafts, a block mounted in one end of the arm and shiftable only endwise thereof, an eccentric strap mounted in the block for said eccentric, eccentrics mounted on the other shaft to turn therewith, blocks mounted in the other end of the arm, one of said last named blocks being shiftable only endwise of the arm and the other of the last named blocks being shiftable only vertically of the arm, eccentric straps supported in the last named blocks respectively for the re spective last named eccentrics, and means operatively connecting the shafts to one another.

25. In combination, an arm, a frame, shafts journaled in the frame, an eccentric on one of said shafts, a block mounted on one end of the arm and shiftableonly endwise thereof, an eccentric strap mounted in the block for said eccentric, an eccentric fast on the other shaft, sleeves on the other shaft, an eccentric fast on one sleeve, a pair of ec centrics fast on the other sleeve, means to prevent relative rotation of the shaft and one of the sleeves, means to adjustably fix the other sleeve relative to the shaft, blocks mounted in the other end of the arm, a pair of said last named blocks beingshiftable only endwise of the arm and a pair of said last named blocks being shiftable only vertically of the arm, eccentric straps supported in the last named blocks respectively for the eccentrics on the other shaft and on the sleeves respectively, and means operatively connecting the shafts to one another.

26. In a dry ore concentrator, a table having its discharge end higher than its intake end and having a perforated oresupporting surface; means to blow air upwardly through the perforations, and means to moilzle a portion of the table in. an elliptical pat 27. In a dry ore concentrator, a table havlng a perforated ore supportingsurface,

'means to blow air upwardly through the perforations, and means to toss the particles of ore toward the discharge end of the table. I 28 In a dry ore concentrator, a table having Its discharge end higher than its intake end and having a perforated ore-support.

ing surface, means to blow air upwardly through the perforations, and means to toss the particles of ore toward the discharge end of the table.

29. In a dry ore concentrator, a table, an means to move a portion of the table in an elliptical path, the movement near the finish of the forward stroke being accelerated upperforations, and means to move a portion of the table in an elliptical path, the movement near the finish of the forward stroke being accelerated upwardly.

32. In a dry ore concentrator, a'table having its discharge end higher than its intake end and having a perforated ore-supporting surface, means to blow air upwardly through the perforations, and means to move a portion of the table in an elliptical path, the movement near the finish of the forward stroke being accelerated upwardly.

33.- In a dry ore concentrator, a table, and means to move a portion of the table forwardly with a final upward rapidly accelerating movement so as to toss the material free of the table, said means returning the table while the material is in suspension.

34. In a dry ore concentrator, a table, and means to move a portion of the table forwardly with a final upward rapidly accelerating movement so as to toss the material free of the table, said means returning the table rearwardly and downwardly while the material is in suspension.

Signed at Los Angeles, California, this 20th day of December, 1917 ALVA w. TYLER.

n a dry ore concentrator, a table hav- I It is hereby certified that in Letters Patent No. 1,397,749, granted November 22, 1921, upon the application of Alva W. Tyler, of Los Angeles, California, for an improvement in Concentrators, errors appear requiring eorrection as follows: lln the drawings, Sheets 1 and 2, in headings, line 5, for 2 Sheets read 3 Sheets; Sheet 3, containing Figures 11 to 14;, inclusive, should appear as shown below as part of the Letters Patent:

arr/gram A/l/M W ,CV/er: Bl

end that the said Letters Patent should be read with'these corrections therein that the same may conform to the record of the case in the Patent ()tfice.

Signed and sealed this 7th day of February, A. D, 1922.

rsme KARL FENNING,

Acting (*mmm'ssz'oner of Patents. 

